Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1612185 | Journal of Alloys and Compounds | 2014 | 6 Pages |
Abstract
Critical behaviors of the half-doped perovskite cobaltites Pr0.5Sr0.5CoO3-Î (Î=0 and â¼0.16) are investigated around the critical temperatures by bulk magnetization study, where the critical exponents (β, γ and δ) are obtained. These critical exponents fulfill the Widom scaling law δ=1+γβ-1, indicating self-consistency and reliability of the obtained results. With the critical exponents, M-T-H curves collapse onto two independent universal branches below and above the critical temperatures. The critical exponents of the oxygen-nonstoichiometric Pr0.5Sr0.5CoO3-Î accord with the mean-field model exactly. However, for the oxygen-stoichiometric Pr0.5Sr0.5CoO3,β deviates to the theoretical prediction of three-dimensional Heisenberg model while γ and δ are close to that of mean-field model. These results indicate long-range ferromagnetic coupling in Pr0.5Sr0.5CoO3âÎ (Î=0 and â¼0.16), which cannot be explained by the nearest-neighbor interaction proposed for the double-exchange mechanism. Instead, the collective effect of p-d hybridization and RKKY interaction of Pr3+ f-electrons with the conduction electrons is suggested to be responsible for the long-range interaction. In addition, the discrepancy of β in the oxygen-stoichiometric Pr0.5Sr0.5CoO3 may be due to a short-range interaction corresponding to the extra crystalline phases in the oxygen-stoichiometric sample.
Keywords
Related Topics
Physical Sciences and Engineering
Materials Science
Metals and Alloys
Authors
Lei Zhang, Jun Fang, Jiyu Fan, Min Ge, Langsheng Ling, Changjin Zhang, Li Pi, Shun Tan, Yuheng Zhang,